Warren is Brown’s Democratic challenger in this year’s Massachusetts Senate race—one of the most closely watched in the nation, and a competition which may very well decide which party controls the Senate in the 113th Congress. The two contestants had their first debate on Thursday night.

“Professor Warren claimed that she’s a Native American and a person of color, and as you can see, she’s not,” Brown said during that debate. “But the fact is, she checked a box.”

Warren, a progressive hero, once claimed on a Harvard job application that she was part Cherokee. She later clarified that she was 1/32 Native American, saying she had been told as much by her mother, and had taken that fact at face value.

Warren’s counter to Brown’s attack? Brown is a “nice” man, and she hopes their contest can focus on the issues.

Frank, who is retiring from the House this year, told msnbc host Rachel Maddow that he was deeply disappointed by Brown’s “snarky” remarks, especially considering that America is struggling economically and is in the middle of a war. Frank said the “personal attack” is “not really consistent with the nice guy image he’s put forward. “

He also pointed out that, in deep-blue Massachusetts, Brown is trying to distance himself from his own party’s brand. You “couldn’t get him to say the word Romney with a subpoena,” the notoriously quick-witted congressman said.